I've seen this plastered upon car bumpers before, and I've seen it on conservative t-shirts, and I've heard conservatives bleat it out when they realize they don't have a chance in an argument. Most notably, when the Patriot Act (the first one) was being hammered out and bandied about the political discourse, lots of righties were using this phrase to justify the dismantling of civil liberties in order to be free. I always thought that was a bit of a circular argument, but I also realized that you just can't reason with some of these folks.
But, after my previous post, I'd like to present this phrase in a different way. No, freedom isn't free. In order to be free, you have to accept that some people are going to take advantage of the system. For example, soldiers coming home from Iraq missing limbs or with serious mental injuries will be (ideally, but not always) qualified for disability benefits. This is because someone thought it would be a good idea to not be an asshole and to help out the people who protect our country and might just boost morale and lessen some of the burden a soldier had to face. It's just doing the right thing. But at some point, someone is going to take advantage of that system. Maybe several someones will take advantage of that system. Conservatives would like to claim, as they do when arguing against national healthcare, that because someone will be able to take advantage of the system that the system should not exist.
I don't know about you, but I'd rather have the system in place and have my taxes go toward helping a lot of truly needy people, in addition to a handful of leeches, than dismantle the whole system so that everybody suffers.
So, yeah, freedom really ISN'T free. But not in the way you think.